Colloid Preload versus Crystalloid Co-Load in the Setting of Norepinephrine Infusion during Cesarean Section: Time and Type of Administered Fluids Do Not Matter

Abstract

Background and Goal of Study: Spinal anesthesia for cesarean section is frequently associated with a high incidence of hypotension, which may bring about untoward effects for both the mother and fetus. Recently, norepinephrine has emerged as a promising alternative in maintaining blood pressure in the obstetric setting. Fluid administration is another technique still widely used to prevent maternal hypotension. The optimal fluid strategy to prevent maternal hypotension has not been elucidated yet. It has been recently suggested that the main strategy in the prevention and management of hypotension should be the combination of vasoconstrictive medications and fluid administration. The aim of this randomized study was to compare the incidence of maternal hypotension in parturients receiving either colloid preload or crystalloid co-load in the setting of prophylactic norepinephrine infusion during elective cesarean section under combined spinal–epidural anesthesia. Materials and Methods: After ethics committee approval, 102 parturients with full-term singleton pregnancies were randomly allocated to either 6% hydroxyethyl starch 130/0.4 5 mL/kg before the onset of spinal anesthesia (colloid preload group) or Ringer’s lactate solution 10 mL/kg concurrent with the subarachnoid injection (crystalloid co-load group). In both groups, norepinephrine 4 μg/min starting simultaneously with the administration of the subarachnoid solution was also administered. The primary outcome of the study was the incidence of maternal hypotension, defined as systolic arterial pressure (SAP) < 80% of baseline. The incidence of severe hypotension (SAP < 80 mmHg), total dose of vasoconstrictive agents administered, as well as the acid–base status and Apgar score of the neonate and any incidence of maternal side effects were also recorded. Results: Data analysis was performed on 100 parturients: 51 in the colloid preload group and 49 in the crystalloid co-load group. No significant differences were demonstrated between the colloid preload group and the crystalloid co-load group in the incidence of hypotension (13.7% vs. 16.3%, p = 0.933) or the incidence of severe hypotension (0% vs. 4%, p = 0.238). The median (range) ephedrine dose was 0 (0–15) mg in the colloid preload group and 0 (0–10) mg in the crystalloid co-load group (p = 0.807). The incidence of bradycardia, reactive hypertension, requirement for modification of vasopressor infusion, time to the first occurrence of hypotension, and maternal hemodynamics did not differ between the two groups. There were no significant differences in other maternal side effects or neonatal outcomes between groups. Conclusions: The incidence of hypotension with a norepinephrine preventive infusion is low and comparable with both colloid preload and crystalloid co-load. Both fluid-loading techniques are appropriate in women undergoing cesarean delivery. It appears that the optimal regimen for prevention of maternal hypotension is a combined strategy of a prophylactic vasopressor such as norepinephrine and fluids.

Comparison of crystalloid and colloid co-load combined with norepinephrine prophylaxis on post-spinal anesthesia hypotension during cesarean delivery: a randomized sequential allocation dose-finding study

“…However, due to their larger molecular weight, colloids are unable to easily cross into the interstitial fluid and remain in the intervascular space for a longer duration relative to crystalloids, promoting superior intravascular volume expansion and increased osmotic pressure ( 22 , 23 ). In a recent study, Theodoraki et al demonstrated that the incidence of post-spinal anesthesia hypotension was low and comparable between colloid preload and crystalloid co-load when combined with prophylactic norepinephrine infusion ( 24 ). This result indicates the potential advantages of administering crystalloid.…”

“…The administration of a rapid crystalloid preload may contribute to the distension of atrial chamber and subsequent stimulation of atrial natriuretic peptide secretion, resulting in peripheral vasodilation and a diuretic effect ( 25 ). Conversely, co-load may result in a lesser aforementioned effect and restrict the redistribution of fluid loading into the interstitial compartment due to the decrease in hydrostatic pressure, concomitant with spinal-induced vasodilation ( 6 , 24 ). Though co-load can help reduce the incidence and severity of post-spinal anesthesia hypotension, additional vasopressors are commonly required to counter arteriolar vasodilation ( 6 ).…”

The Effect of Adding 1% Glucose to Crystalloid on Maternal Hemodynamics After Spinal Anesthesia for Cesarean Delivery: A Double-Blind, Randomized Clinical Trial

“…However, this difference was not significant. In the literature, the incidence of hypotension ranges from 13% to 90% (5,6,12,(23)(24)(25). Most studies have compared the incidence of hypotension between preloading with colloids and crystalloids.…”

“…Colloid solutions have been shown to have a superior effect compared to crystalloids in preventing hypotension in several studies (10,11). However, recent studies have reported contradictory results (12,13).…”

“…In addition, administration of large volumes of colloid preload has been reported to have no additional benefits. It may also have adverse effects such as anaphylactoid reactions and renal function impairment (12,14,15). Based on a systematic review of the administration of both preloaded and concomitant crystalline and colloidal fluids, fluid therapy can reduce the incidence of hypotension; however, a vasopressor should be used for complete reduction (16).…”